Glass workability during the forming process has been discussed from the aspects of rheology, heat transfer, and microstructure. The rheological behaviour and heat-transfer characteristic of glass determine the workability of glass. However, accidentally caused changes of glass structure during melting, fining and forming can affect workability. Therefore, the apparent liquidus temperature and crystal structure of bad workability glass have been studied and compared with good workability glass. It is found that the apparent liquidus temperature study seems to be an effective method for determining the good and bad workability glasses. Results from the mechanical strength study of the good workability glass shows evidence of microvoids of the order of 400A existing in the glass structure.
